This invention relates to an exhaust braking control apparatus for controlling exhaust gas flow through an engine exhaust passage to provide an engine braking effect
It is the current practice to increase an engine braking effect by using a control valve to close the engine exhaust passage, causing the engine to operate like a compressor. However, such a prior art exhaust braking control apparatus can operate only in two modes. In the first mode, the exhaust braking control apparatus sets the control valve at its fully-open position permitting free exhaust gas flow to the atmosphere, and in the second mode, the exhaust braking control apparatus sets the control valve is at its fully-closed position to provide exhaust braking. It is, therefore, impossible to provide an appropriate degree of engine braking effect over the entire range of vehicle operating conditions.